The Murder of Harriet Krohn, Karin Fossum
Karin Fossum is a prize-winning Norwegian author whose many books have been translated into multiple languages. She's an awesome writer - I've enjoyed every one of her previous novels.
In The Murder of Harriet Krohn, Fossum tells the story from the point of view of a murderer. She really gets into the twisted mind of this older man whose gambling addiction leads him to depraved thinking and behaviour. In fact, she's so successful that I found myself too uncomfortable to read any further. So I put the book aside after getting maybe a third of the way in.
It's just scary how some people think.